Process of making copper hydroxide



Patented July 25, 1933 TE r ssica HARRY r. sassnru or- GYNTI-IIAITA, KENTUCKY, nn snw'srr o. s Mons-or' PHILA- DELPHIA, PENNSYLVANIA; AssIenons 'ro ianres sassnrr & stauen'rns, 11m,

' ,orrniinanntrirm,PENNSYLVA I ,nooaroiai rioiv or rEivNsYLv niA I rnoonss FMAKING No Drawin a a lication filed June 17,

This invention relates to ai process of ing copper (cupric) hydroxide and more particularlytoa process ofmaking copper toprovide' a process of making copper hyof arti droxide in extremely pure condition;

provide a process of. making copper hy-" droxide which. is particularly'adapted, for] usein preparing cuprammonium solutions for use in the manufacture-of artificial silk andth'e like. V

Otherobjects ,an'd'advanta'ges of themvention will become apparent during the course of the following description;

According to one of the most generally used processes of making copper hydroxide, copper sulfate is mixed with sufficient caustic soda to react with the'copper salts and provide a solution which is substantial neutral or only slightly alkaline.- The precipithis is a simple method of making copper hydroxide, the resulting product ordinarily contains from l'to 20% of basic copper salts with the result that it is too impure for certainfpurposessuch as inthe manufacture cial silk according to the. cuprammonium process. A further disadvantage of the product for use in the artificial silk industry is that there is a' waste of copper in the process due to thefact that the copper of the basic copper sulfate is not in an active condition to form a cuprammonium solution with ammonia. Moreover, the presence of basic copper sulfate in a 'cuprammonium' spinning solution is detrimental as it clogs up the spinnerettes.

In the present process of making copper hydroxide which is particularly adapted for use in preparing cuprammonium solutions, a

concentrated copper sulfate solution is reacted with an excess of caustic alkali at a temperature below G. In the preferred practice of the process, an aqueous solution of copper sulfate in as concentrated condiof artificial silk oorrnn HYDROXIDE 1830i Serial No. 461,848;

tion as possible without crystallization is tic alkalies,jsuch as potassium hydroxide,

may be employed. Asfstated, the caustic alkali is -lised in solution, the strength of which may hevaried, although we prefer to w'employ a. jNaOH' solution. The pur- .A further'objectof the invention \is to" per sulfate which'is formed;

As indicated, the reaction should be coni 4 C. is generally most advantageous. The V purpose of the low temperature is to facilitate the settling of the copper hydroxide formed. We have found that the useof a reduced temperature results in the formation of larger and heavier particles of 'copper hydroxide which more readily settle j than the particles formed when thereaction tate which forms is fitered for use. While,

is conducted ata higher temperature.

After the reaction, care should be taken to collect the copper hydroxide promptly. For example, if the mass is allowed to stand for several hours, say 6 hours, the copper hydroxide formed breaks down into the brown cuprous oxide. Accordingly, we have found it advantageous to hasten the settling of the copper hydroxide by adding a settling agent to the mass. settling agents may be employed it is advisable to select one which will not substantially react with the copper hydroxide and which will not be detrimentallto the silk when the copper hydroxide is to be employed in the preparation of cuprammonium solutions for use in the manufacture of 'ar} tificial silk. coagulating agents such as glucoseor common soap, or agents which lower. the surface tension of the solution, such as ethyl alcohol or glycerine may be advantageously used as settling agents in the practice of the process. l/Ve preferto employ glucose and when this material is used we add the glucoseto the mass in the While various I proportions of approximately of 1% on the weight of the copper hydroxide present.

After the addition of the settling agent, the mass is allowed to stand until the copper hydroxide has settled. quires about two hours. Thereafter, the supernatant liquid is drawn oil and the pre cipitate is washed with water, preferably by mixing water with theprecipitate "and stirring. While the resulting copper 11y dioxide is comparatively pure, it is adv s= able to let the mass stand again for approxi-v mately two hours, draw off the supernatant liquid, and again wash. In the particular embodiment to which we have put the present invention, the settling and washing may be conductedany number of times in order to assure the absenceof water soluble im-' purities in'the final product. 1 Afterthe final washing the product is filtered and dried,

This ordinarily reaqueous solution of copper salt with from 105 to 120% of the theoretical reaction amount of ail-alkali metal hydroxide in solution, immediately adding glucose to the mass, allowing the mass to stand to permit the copper hydroxide to settle, and separating and washing the precipitated copper hydroxide. r

2. The herein described process of pre paring copper hydroxide which comprises mixing at a temperature of approximately 2to4 Gaaneaqueous solution ofcopper salt with an excess of the theoretical reacting amount of; analkali metal hydroxide insolution, immediately adding glucose to the mass, allowin the masstostand to permit the copper hydroxide to settle, and separating and washing the precipitated copper hydroxide.-

3. The herein described process of preparing'copper' hydroxide which comprises mixing at a temperature of approximately from 2 to 1 C. an aqueous solution-ofcopper salt with approximately 110% of the theoretical reacting amount of an alkali metal hydroxide in solution, immediately adding glucose to theimass, allowingtheimassto stand to permit-the copper hydroxide to settle, and separating and washing a plurality of times theprecipitated copper hydroxide,

r HARRY P; BASSETT. 7 JEWETT C. SIMONS. 

